Loading

wait a moment

Risk and Severity of COPD Is Associated With the Group-Specific Component of Serum Globulin 1F Allele: Statistical Analysis

Risk and Severity of COPD Is Associated With the Group-Specific Component of Serum Globulin 1F Allele: Statistical AnalysisTo test Gc-globulin phenotypic variance between patients with COPD and healthy smokers, and to compare the frequency of individuals over or under the threshold (dFEV1 > 90 mL/yr, LAA% > 60%, or mean CT score < — 940 HU) in the two populations, asymptotic normal tests for the equality of two population probabilities were performed. A Welch test was employed to test the difference of population averages in continuous variates between the two groups. StatView Version 5.0 (SAS Institute; Cary, NC) was used for the statistical calculations; p < 0.05 was considered statistically significant. more
Results
Subject Characteristics

The baseline characteristics and the results of baseline pulmonary function tests of 103 patients with COPD and 88 healthy smokers are shown in Table 1. In the initial evaluation of patients with COPD, 9 patients were classified in stage I, 38 patients were in stage IIA, 37 patients were in stage IIB, and 19 patients were in stage III. The evaluation was performed according to the Global Initiative for Chronic Obstructive Lung Disease guidelines.
Genotyping
Gc-globulin allele frequency and genotype frequency in each group are shown in Table 2. Allele frequencies for the healthy smokers were as follows: Gc*1F, 0.49; Gc*1S, 0.27; and Gc*2, 0.24. These values were similar to the reported allele frequencies from large studies in the Japanese population. Allele frequencies for the patients with COPD in the present study were as follows: Gc*1F, 0.58; Gc*1S, 0.22; and Gc*2, 0.19. Although there were no significant differences in allele frequencies between the two groups, there was an increased proportion of Gc*1F homozygotes in the patients with COPD (32%) compared with the healthy smokers (17%) [p = 0.01; odds ratio, 2.3; 95% confidence interval, 1.2 to 4.6]. The baseline FEV1 percentage predicted in patients with COPD and with Gc*1F alleles (ie, 1F-1F, 1F-1S, and 1F-2) was not significantly different from that in patients with COPD without it (ie, 1S-1S, 1S-2, and 2-2) [44.8 ± 17.9% vs 48.4 ± 21.3%, p = 0.54].
Table 1—Baseline Characteristics of Study Subjects

Subjects Men/Women,

No.

Age, yr Smoking History, Pack-Years FEV1, L FEV1, % Predicted FEV1/FVC,

%

Patients with COPD (n = 103) 99/4 67.4 ± 7.8 58.3 ± 29.1 1.18 ± 0.49 45.3 ± 18.4 45.8 ± 10.4
Smoker control subjects (n = 88) 72/16 60.8 ± 12.0 41.1 ± 22.2 2.66 ± 0.86 88.4 ± 20.7 80.1 ± 7.8

Table 2—Allele and Genotype Frequency in COPD Patients and Healthy Smoker Control Subjects

Variables Patients With COPD (n = 103) Control Subjects

(n = 88)

p Value
Allele
Gc*1F 120 (58) 87 (49) 0.094
Gc*1S 46 (22) 47 (27) 0.22
Gc*2 40 (19) 42 (24) 0.22
Genotype
1F-1F 33 (32) 15(17) 0.014
1F-1S 29 (28) 27 (31) 0.70
1F-2 25 (24) 30 (34) 0.14
1S-1S 3(3) 5 (6) 0.35
1S-2 11 (11) 10(11) 0.88
2-2 2 (2) 1(1) 0.65